The top experimental drug stemming from Johnson & Johnson’s long-running alliance with Addex Therapeutics has failed a Phase 2 epilepsy study, casting a shadow over its future.
The candidate, ADX71149, did not make a statistically significant difference in time to baseline seizure count when added to the standard of care. Addex is still analyzing the data and will work with its partner, J&J, to determine the next steps for the program, Chief Medical Officer Roger Mills said in a statement.
Roger MillsADX71149 is the lead candidate in Addex’s pipeline, and the only named compound in the biotech’s collaboration with J&J to develop positive allosteric modulators of the mGlu2 receptor since the deal was announced in late 2004.
J&J’s Janssen unit, which is in charge of development, had previously run Phase 2a studies of the compound for schizophrenia and anxious depression. It never moved forward in schizophrenia despite encouraging data, while it failed to show statistically significant effects in anxious depression.
Janssen first flagged the drug’s potential in preclinical models of epilepsy in 2015 and started a Phase 2 trial in 2021. That study enrolled 110 patients with focal onset seizures who saw suboptimal response to levetiracetam or brivaracetam. Patients were given ADX71149 on top of either of those two common treatments, plus up to three other anti-seizure drugs.
Addex received around $5 million (CHF 4.6 million) upfront and around $7 million in research funding (CHF 6.4 million) in the early years of the J&J pact, and has since collected a small portion of the €109 million promised in milestones, according to regulatory filings.
The biotech counts one other clinical-stage program, dipraglurant, in the pipeline, but it’s looking for ways to take the drug forward after scrapping a Parkinson’s trial due to Covid-related enrollment challenges.
With a minuscule market cap on the Swiss stock exchange, Addex recently spun out a new company called Neurosterix to develop some of its earlier-stage assets. On Monday, it said Indivior, under a collaboration around GABAB-positive allosteric modulators, is on track to select candidates for IND-enabling studies in June.